This invention relates to a platform to be maintained at high altitudes by a net momentum transferred to the platform by atmospheric particles.
The purpose of the platform is to receive and to emit electromagnetic waves, as well as to carry light weight instruments. These instruments may, for example, perform atmospheric observations, or receive electromagnetic signals.
Since the platform is located at high altitudes, it can emit signals to, and receive signals from areas of the earth which lie well beyond the horizon of an observer located on the surface of the earth directly below the platform. Therefore, an instrument carried by the platform can observe areas well beyond that same horizon. Additionally, since the platform is located above much of the atmosphere, particularly its densest layers, an instrument carried by the platform can perform astronomical observations without interference from those layers.
The quality of communication by electromagnetic waves is generally enhanced if the emitter is in the direct line of sight of the receiver. The area within which direct line of sight communication is possible with a given emitter, is larger if the emitter is located higher above the surface of the earth. Therefore, one way to extend the area of good reception from a given television emitting antenna, is to locate the antenna on a tower. However, the height of towers is limited. To achieve larger areas of good television reception, one has to use relay stations, cables or earth orbiting satellites. The present invention provides an alternative: a platform suspended in the atmosphere by a net atmospheric particle momentum transfer. The purpose of the platform is the reception and emission of electromagnetic waves, such as television waves.
Surveys of large areas of the surface of the earth are useful for a wide variety of purposes, including the detection of forest fires, the study of traffic patterns, and the observation of natural disasters. At the present, such surveys are carried out from aircraft, balloons or earth orbiting satellites. This invention provides the means for locating light observing instruments on a platform floating at high altitudes in the atmosphere.
Any direct contact measurement of atmospheric properties at high altitudes is usually carried out by instruments located on aircraft, balloons, rockets, and occasionally on earth orbiting satellites. These same means of transportation are used to lift astonomical telescopes to altitudes above much of the atmosphere, in order to enhance the accuracy of observation. The present invention makes it possible to raise instrumentation to high altitudes by locating them on a platform as described below. Such instruments may be used to perform direct contact atmospheric measurements, as well as astronomical observations.
One method to keep a platform afloat and/or to move it or change its orientation in the atmosphere was described in my prior U.S. Pat. No. 4,253,190 issued on Feb. 24, 1981, entitled "Communications System Using a Mirror Kept in Outer Space by Electromagnetic Radiation Pressure". According to that patent, a communications mirror is kept afloat and can be raised, lowered or be moved horizontally and reoriented through forces exerted by electromagnetic radiation beamed at the mirror from a man-made installation.
The purpose of the present invention is to improve on and to expand the method described in the mentioned patent in several ways, including the following:
1. The platform may be kept afloat and moved by less radiation beamed at it. PA1 2. Conditions may be arranged so that the desired acceleration or floatation occurs as a result of utilizing natural sources of heating, such as radiation from the sun (without any man-made radiation beamed at the platform, and also without any artificial means of heating the platform). PA1 3. Smaller antennas may suffice to direct and receive the radiation when the wavelength is shorter. PA1 4. The platform may serve not only as a passive reflector, but also as an active reflector, an instrument-carrying platform.
With the recent progress in microfabrication techniques, instruments weighing no more than a few grams are capable of performing important tasks, such as transmitting, receiving and processing information. The invention to be described here will make it possible to locate such lightweight instruments at high altitudes, at relatively low cost. By contrast, the methods in general use today require a relatively heavy (and expensive) lifting structure, such as a rocket, airplane or balloon, for lifting any payload whether heavy or light.
It will become clear from the following description of the present invention that this invention utilizes a mechanism which differs from conventional methods of keeping an object aloft, or accelerating it in an atmosphere.
Indeed, satellites and rockets can keep a platform aloft even in the absence of a surrounding atmosphere. By contrast, the present invention utilizes the presence of a surrounding atmosphere; in the absence of an atmosphere the invention to be described can not be used.
On the other hand, airplanes and helicopters stay aloft only as long as they themselves, or a part of them (the propeller) moves with sufficient speed with respect to the surrounding atmosphere. By contrast, the present invention makes it possible to keep an object aloft even if all parts of the object are at rest with respect of the surrounding atmosphere as a whole.
Finally, for a balloon to stay aloft, it is necessary that the hydrostatic pressure at the top and bottom of the balloon be sufficiently different. By contrast, the present invention enables one to keep a platform afloat, even if the hydrostatic pressure at the top and bottom surface of the object is the same.
In the following discussion I will use the phrase "atmospheric-particle-momentum-transfer-characteristics" of a surface of an object to mean those characteristics of a surface which determine the magnitude and direction of the momentum transferred to the object by atmospheric particles impinging on the surface.
This invention provides a method for imparting an atmospheric-particle-momentum-derived net force on an object having at least two surface portions appropriately disposed thereon. The net atmospheric particle momentum transfer characteristics between the two surface portions are different. An object which has these characteristics will be referred to as a "platform".
The platform is placed in the atmosphere, in a region having a generally known distribution of temperature, density and composition with the surface portions exposed. A temperature differential is established between at least one of the surface portions and the atmosphere. As a result, different atmospheric particle momentum transfer occurs on the two surface portions. This results in a net force being applied to the platform.
These and other objects and advantages of the present invention will be more clearly understood from a consideration of the drawings and the following detailed description of the preferred embodiments.